OTTAWA — Transport Canada is investigating the cruise ship Queen Elizabeth 2 for dumping three tonnes of paper pulp off the coast of Cape Breton last year.

The ship dumped the waste on the evening of Sept. 8, according to a pollution report obtained through federal access to information legislation. It happened during a five-hour period when the vessel was travelling between the northern tip of Cape Breton and the southern shore of the island.

Transport Canada officials have been investigating since the pollution was reported by the cruise ship the following day. The ship’s owner, Cunard, a subsidiary of the Carnival cruise company, could be facing fines.

"The reason it was not publicly announced that there were allegations against the QE2 is that it is not our policy to report allegations publicly," Transport Canada spokesman Steve Bone said Monday.

"Our policy is to make an announcement by means of a press release or publishing the outcome on our website after a charge is laid and we have a successful prosecution."

As part of its investigation, Transport Canada "will visit the vessel when it returns to a Canadian port, to gather evidence and interview crew members," Mr. Bone told The Chronicle Herald in an earlier interview.

Officials from Cunard declined comment on the matter.

Ships are required to keep a log of their garbage activities, which will likely be of interest to Transport Canada investigators.

Environment Canada emergencies officer Annie MacNeil, who received the original pollution report last year, said the type of waste is unusual — bilge oil or chemical spills are more common.

Paper pulp qualifies as garbage under Canada’s marine pollution regulations, and it’s prohibited to dump it in Canadian waters.

Paper products are not considered as serious as other substances, and Clarke Wiseman, an enforcement officer with Environment Canada, said that without a sample of the original waste, it will be difficult to tell whether any environmental damage was caused.

"This was something like shredded paper — it was nothing of a wood pulp nature, but I’m not sure of that," Mr. Wiseman said.

The pulp could have been from a toilet paper product, he said. Depending on the type of paper, it could have taken days or several weeks for it to dissolve.

Mr. Wiseman said paper pulp would have had little or no influence on fish, although it could have had negative effects by blocking sunlight or draining oxygen from the water.

But if the paper pulp was treated with chemicals, it could have been a hazard to birds and other animals.

Ross Klein, author of Cruise Ship Squeeze: The New Pirates of the Seven Seas, said he is concerned that pollution within the cruise industry is not effectively regulated by the Canadian government.

"The government really hasn’t taken an interest in standing up to the cruise industry," Mr. Klein said.

Environmental regulations are unevenly enforced around the world, he said, and it is unfair that cruise companies are not required to contribute to cities’ harbour cleanup costs.

But Ms. MacNeil, who has "been on the receiving end of pollution reports for a number of years," said Environment Canada does not have a specific issue with the cruise industry.

Transport Canada has up to three years to complete the investigation. Mr. Bone said working quickly is difficult with international vessels.

"Should there be sufficient evidence and if warranted, Transport Canada will prosecute under the Canada Shipping Act," he said.

Pollution fines are set by a trial judge, so they vary. For garbage pollution, fines are typically in the thousands of dollars.

Smaller ports, such as St. John’s are actively encouraging cruse ship companies to visit. The economic benefits of even short stays can be considerable.

The Queen Elizabeth II is scheduled to return to Atlantic Canada in the fall, with the first stop in Halifax on Sept. 23.